>actual low oil pressure...

(...caused by a pressure relief valve that didn't seat properly when
coming off of high engine rpm in hot weather?)

The fix for an intermittent oil pressure alarm (buzzer plus light) on
a 1990 Westy (as described above), was to replace the spring on the
oil pressure relief.  Can't remember where the spring resides.  I
remember only thinking how simple the spring replacement had been.

g